Seismograph.



Patented Apr 28, 1914.

- 3 SHEETSSHEET l IIIIIIIIFIIII Z 0 "I a mm W W A WWI T. OBRIEN.

.SEISMOGRAPH.

APPLICATION FILED DEO.6,1912,-

T. OBRIEN.

SEISMOGRAPH.

APPLICATION FILED DEG. e, 1912.

Patented Apru28-,1914.

3 SHEETS-SHEET 3.

' work.

. in portable. instruments of this kind to inmovements are required.

' as all calculations of relative movement are recording simultaneously both horizontal gineering works, and at all places where ac- THOMAS OBRIEN, or BROOKLYN,

NEW YORK, A SSIGNOR TO HENRY G. OPDYCKE, OF NEW YORK, N. 'Y.

SEISMOGRAPH.

Specification of Letters Patent.

Patented Apr. 28, 1914.

7 Application filed December 6, 1912. Serial No. 735,337.,

Yballwhbm it may com-em:

' Be 'it known that I, THOMAS OBmnx, a citizen of the United States, residing at Brooklyn, in the county of Kings and State of New .York, have invented certain new and useful Improvements in Seism'ographs; and I do hereby declare the following to be a full, clear, and exact'description of the invention, such as will enable others skilled in the 'art to which it appertains to make and use the same. 4

This invention is an improvement in portable seismographs designed for measuring and recording vibrations in buildings, and in i connection with general engineering The principal object of this invention is sure more accurate results in the measurement of vibrations without increasing the total weight to be carried by substituting a single inert mass or pendulum to be used in and vertical movements'instead of two pendula aggregating the same weight and of similar density, as used heretofore; the functional utility of the mass being thereby doubled. I

Another object is to provide an improve ment in portable seismographs, such as gen orally used in measuring and recording vibrations in buildings, bridges and other encurate determinations of'the amplitude and energy of both the horizontal and vertical Separate pendula have been used hitherto for this purpose and dependent for their accuracy upon the assumed stability of an inert mass, the advantages incident to the use of a single pendulum are apparent, the operation of an additional lever absorbing only a negligible amount of vibrational energy.

Another object of this invention is topr'ovide means for detaching a pendulum for the instrument, thus preventing injurious impact with more delicate parts thereof through careless handling, neglect or accident. 7

.Another object of this invention is the simplification of portable instruments ofl rigidly attached to thependulum at a point horizontally coincident with its axial line of suspension. I

A further object of this invention is to provide simple means for rapidly placing and securing prepared charts on the cylinder by slot-ting the cylinder for the admis sion of two ends of the charts and aflixing flexible buttons at near eitherend on the inner periphery, a quarter revolution of which will yield the requisite frictional pressure.

Further objects will be apparent from the following specification, appended claims and drawings, in which Figure 1 is a plan view of my device showing parts thereof'in section, Fig. 2 is a front elevation thereof showing parts broken away, Fig. 3 is an elevation of the pendulum showing its mounting and recording levers. Fig. 4 is a perspective view of the magnifying levers for recording the vertical vibra tions of the. pendulum, Fig. 5 is a similar view of the magnifying levers for recording the lateral vibrations of the pendulum. Fig. 6 is an end view of the recording drum showing the gear connections to a clock to impart rotary motion to the drum and longitudinal motion to the carriage which supports said drum, Fig. 7 is a perspective view of a portion of one of the recording levers, Fig. 8 is a perspective view of the. means employed in fastening the record sheet to the drum, Fig. 9 is a plan view of the supporting means for the pendulum shown'in Fig. 3, and Fig. 10 is a perspective view of one of the cheek members used to prevent oscillations of the pendulum in certain lateral directions.

In instruments ofthis character. it is desired to provide a pendulum with. a supsupports a recording drum 13- having a recporting member which supporting member is carried by a base and whichbasefcarries av record sheet upon which to-re'cord an brations of the pendulum with respecht the base. In this particular case it" -is-"ne'cejssary to restrict the horizontal niov'ement ofithej pendulum with respect to the baseto-a -certain plane (the movement being freef'wh en the plane of the base is made coincident) and as it is desired also to record any relative vertical movement of the pendulum, it is necessary that a special construction be provided to permit vertical and 'lateral movement of the pendulum without mutual interference or disturbance of alinement of the several transmitting levers. To this end I provide a base 10 provided with tracks 11 upon which is mounted a carriage 12 which 0rd sheet secured thereto. At any desired position with respect to said drum, I provide a standcomprising the uprights 14and platdulum 2-1.

form 15 upon which is mounted the'supporting means for the pendulum'caThis support ing means comprises a plurality of springs.

16 which are supported bythe-base 15 and bear against a flange onzflanges 17, carried by a stem 18, which ste lower end with an eye 19 or other supporting ';provided at its receive the cord Q for the pen- The support of an iner't'mass by a plurality of springs instead of a single spring is claimed as an improvement as and for the reason that the ratio qofsresistance to torsional strain in a sprin'g has its expression in the terms of a series,therefore, a spring capable of maintaining'in equilibriu na mass of say twenty'pounds has a more. extended range of relative vertical movement than one capable of sustaining say one .hundred and twenty-pounds. The interference then with the inertia'of such a suspended-mass as the latter, if sustained by say sixj-springs 5 instead of one, should-vibrational movementdisturb the commonvbase would be directly proportionate to range of movement indicated by torsional strain set up in the heavier and lightersprings. I have shown three springs but it is to be understood that more or less may be used as desired and the purpose of the use of a plurality of springs is to assure against any differential deflections common to a single spring incident to I any two portions thereof. When it is desired to remove the pendulum, the Weight thereof may be removed from the several springs 16 in the following manner. Rising from the platform 15 are standards 22 which support the platform 23 through which the ;.threaded end of the stem "18 passes and upon this ,threaded portion is the removable hand-wheel 24 which by rotation in the proper direction bears against the platform 23 and raises the stem 18 above the by the standardil i.

action of the springs 16. The pendulum 'thenbeing blocked from. below and the hand-wheel removed, 'CaIIbe; readily de tached for separate portage.

I restrict thehorizontal movement of the pendulum 21 to the plane of the-base (for the reasons before stated) cheek plates whichmay be of any cross sectional shape but I have shown them in the. shape of an X as this form gives the best bearing surface with the least resistance. These cheek plates may besupported by any desired means as for instance. bv the angle irons 26 supported Vertical'vibrations of the pendulum with respect to the remainder ofthe apparatus are recorded in the following-manner and throughthe system of levers clearly shown in Figja of the drawing. Risin from the pendulum is a standard 27 to which the upper end. of a link 28 is secured and to. reduce any tendency of a horizontal vibration from.

affecting this link, the upper connection with the -standard 27.-is in alinementwith but. in advance of the connection. for the pendulum supporting medium. 'ThiS link is counected'as by cone'bearings to a bell crank lever 29 which is fulcrumed-as at 30. to a cross bar 31 which cross bar is supportedwheels 40 by which the screws are rotated toadjust. the bar 37.

. #Fig. 5 of the drawing shows a series of levers employed in recording the relative lateral-vibration of the pendulum parallel to the longitudinal dimension of the frame. Secured. to the pendulum as at 41is one end of a link 42 which has the opposite end thereof connected to the lower end of a lever 43which is fulcrumed as at 44 to the cross bar 45 which cross bar4t5 is supported by two of the standards 14. The upper end of the lever 4.3 is quite similar in construction with the arm of the lever 32 so that the description of the construction of the lever 32 will suflice. For purposes of distinction in subsequent description of the invention the lever for recording the lateral vibrations may be designated by the numeral 46.

The levers 32 and 46 may be swung from contact with the record sheet by adjusting the bar 37 so as to cause the rollers 36 carried thereby. to forcibly contact with the plates or ,Iuards 35 and therebyswinzr the levers 33 and 4-6 in a vertical direction sufiiciently far to permit removal and application of the record sheet. "These plates 85 serve 'to prevent any twisting of the vertical levers drum and'passing the other 'end through the same slot, the ends being held in position by the revolving buttons attached to" its inner periphery as shown vin- Fig. 11, so that as the drum rotates the recordsheetrotates and also moves. long1tud1nally as hereinafter shown so as to avoid the imposition of one series of records on another. The drum 13 1s proy1ded-w1th the usual heads which are mounted upon a. shaft 47,w h1ch shaft- 1s mounted in bearings carried by the carriage l2 andthis shaft is rotated byathe pmion 48 meshing with the gear 49 carried by the arbor 5O of'the clock 51.

The ratio of the gears 4:8 and 49 is such that the drum will rotate sufliciently fastto remove the recorded vibrations from the path of further records and is shown to be three to. one. The gear 49 meshes with an idler 52 which in turn meshes with a swingi'ng idler 53'through which motion is trans- I'Ilittd through atrain of gears 54,55 and 56 to a Wormgear 57 which meshes .Wlt-ll a rack 58 secured to the base 10 When it is desired to increase the speed of the longitudinal movement I provide a series of idlers which maymeshwlth a gear 53 to increase the speed of the rotation thereof and referringto the'drawings 59 indicates an idler whiclris intended to produce two movements of the gear 53 to one revolution of the idler 52 and the idler 60 is intended to produce three revolutions of the idler 53 to'the one of he idler 52. The idler 53 is carried by an arm 61 which-is fulcrumed on the shaft of the gear 54.and the arm 61 is swung by the handle 62. The carriage 12 is mounted upon rollers (33 which run on the tracks 11 formed in the base.- i

\Vhen .it is desired'to ascertain the extent of vibration in certain directions as in struc rural work, the apparatus is placed to al- .low oscillation ofthe pendulum in the desired direction. Then as any vibration of the foundation upon which the base of the :mparatus is placed,.occurs, the movement of said base with respect to the inert mass causesthe lever intended for recording the horizontal vibrations, to create a .record upon a specially prepared chart carried by the cylinder. The lever intended for recording the vertical vibrations can operate irrespectively of the lever for recording the horizontal vibrations, and therefore, the vertical vibrations may be recorded with the apparatusplaced in any normal position.

When it is desired to transport the ap paratus, manipulation of fastened to the drum hand Wheel on the t-hreaded stem of the pendulum supporting bar allows the pedulum to be raised-to enable a temporary support to be placed under the pendulum, when the supporting wire or cable may be released and the penduluni detached.

Modifications may be made within the scope of this invention and I do not restrict myself to the identical form shown which is submitted for illustrative purposes only.

Having thus described my invention, I claim: 7

1. In a portable selsrnograph, a single pendant mass or pendulum fitted and adapted to perform double functions of two separate pendula in the matter of measuring and recording horizontal and also vertical vi brations.

Q. In a portable seismograph, a single pendulum, a plurality of springs sustaining said pendulum, a platform sustaining said springs,.and a base rigidly connected with and sustaining said platform.

3.111 a portable seismograph, a base, a pendulum carried thereby for universal movement therewith, separate levers suitably'fulcrumed to said base and jointedly connected with said pendulum and capable of responding freely to any relative movement of said base with regard to said pendulum, said separate levers having extension points for contact with a suitably prepared chart.

4. In a portable seismograph, a record cylinder, a pendulum, said cylinder having an axial and circumferential movement, and said pendulum having a horizontal and vertical freedom of movement, and levers connected to said pendulum'to record vibrations on said cylinder, said levers having freedom of movement in their intended direction independent of each other.

5. In a portable se'ismograph, a record cylinder and pendulum, levers connected to said-pendulum to transmit and magnify vibrations of'said )endulum with respect to said cylinder, s ai levers being connected to transmit the intended vibrations independent of others and means to limit the vibratory movement of said pendulum in certain directions.

o. In a portable seismograph,a suspended pendulum, a support for said pendulum, a base for said pendulum and support and a plurality of springs interposed between said base and support. 7. In a portable seismograph, a single pendulum, an extension rising therefrom. .1621118 providing for the transmission of amplified vertical vibrations without intcrference from horizontal vibrations, said means comprising a lever fitted and provided to transmit such vibrations, connection from said lever tothe extension rising bein and liorlzontal directions, and means for refrom said pendulum at a point correspondmg to the center of the arc of oscillation and where consequently only an upward and downward movement of the pendulum can be transmitted to such lever.

8.. In a portableseismograpli, a base, a pendulum suspended 011 said base, a support carried by said base for said pendulum, a plurality of spring interposed between said support and said pendulum, said pendulum mounted for oscillation in vertical stricting certain horizontal oscillations of said pendulum.

9. In a portable seismograph, a base, a 1

specially prepared record slieetjlevers car'- ried by said base for making a record on said record sheet, said levers being fulcrulncd in directly to said base, said levers having In testimony \vhereoI'I aflix 'my signature -3.

in presence of two Witnesses.

THOMAS OBRIEN. Witnesses:

GEORGE L. -THOM, HUGO Moon. 

